Centrifugal extractor



Jan. 5, 1954 CALL 2,665,008

CENTRIFUGAL EXTRACTOR Filed Sept. 12, 1950 Ian I if I Howard L. Call /2 INVENTOR.

35 1 BY W M009 HM Patented Jan. 5, 1954 UNITED STATES PATENT cringe- CENTRIFUGAL EXTRACTOR Howard L. can, Ogden, Utah 7 Application 1 Claim.

September 12, 1950, Serial No; 184,416

This invention relates to new and useful improvements and structural refinements in centrifugal extractors, and the principal object of the invention is to facilitate preparation of dental amalgam fillings, this being achieved byseparating mercury and other excess fluid from the amalgam mixture.

An important feature of the invention resides in the provision of means in the centrifugal extractor for collecting the extracted mercury and other excess liquid, while another feature lies in the provision of means for rapidly rotating the extractor by a flexible shaft, such as, for example, the shaft of a dental drill.

Some of the advantages of the invention reside in its simplicity of construction, in its efficient and dependable operation, and in its adaptability to economical manufacture.

With the above more important objects and features in view and such other objects and features as may become apparent as this specification proceeds, the invention consists essentially in the arrangement and construction of parts as illus trated in the accompanying drawings, in which:

Figure 1 is a perspective view of the invention;

Figure 2 is a vertical sectional view, taken substantially in the plane of the line 2--2 in Figure 1;

Figure 3 is a fragmentary top plan view of the subject shown in Figure l; and

Figure 4 is a fragmentary sectional detail, taken substantially in the plane of the line 44 in Figure 3.

Like characters of reference are employed to designate like parts in the specification and throughout the several views.

Referring now to the accompanying drawings in detail, the invention consists of a centrifugal extractor for dental amalgam, the extractor as a whole being designated generally by the reference character In and embodying in its construction a dish-shaped housing l2 supported in an elevated position 'by a plurality of legs l4, the housing [2 having a bottom provided with an aperture Hi to accommodate an externally screw-threaded bushing l8 which is secured in the bottom by a suitable nut 20.

The bushing l8 affords a bearing for a diametrically reduced portion 22 of a vertical shaft 24, the shaft portion 22 being slidably and removably positionedin the bushing I8 with a shoulder 26 of the shaft 22 resting on the upper surface of the bushing, as shown.

A horizontal arm 28 is secured intermediate the ends thereof to the upper end of the shaft 24 and one end portion of this arm i screw threaded, as

.2 I at 30, to carry a screw threaded, adjustable counterbalance or counterweight 32, the purpose of which will be hereinafter described.

The remaining end of the arm 28 has secured thereto a flanged, internally screw-threaded annulus 34 supporting a substantially cylindrical receptacle 36 for amalgam material.

The receptacle 36 is provided at its outer side with an internally screw-threaded adapter 38 supporting a removable collecting bowl 40, it being noted that a passage 42, provided with a counterbore 44, is formed in the adapter 38, whereby the interior of the bowl 40 communicates with the interior of the receptacle 36.

The bowl 40 is provided at the outside thereof with a screw threaded, removable drain plug 46, and a cup-shaped separating screen 48 is positioned in the passage 42 and has a flange 56 which is seated in the counterbore 44 and is removably retained therein by an annular keeper 52.

When the inventionis placed in use, a conventional flexible shaft 54 of a dental drill, equipped with a chuck 56, is connected to the portion 22 of the shaft 24 which projects downwardly through the bushing l8, and amalgam material is positioned in the receptacle 36. Thereupon, by driving the shaft 24 at a rapid rate, rotation will be imparted to the arm 28 and mercury and other excess liquids will be centrifuged from the receptacle 36 through the separating screen 48 into the collecting bowl 40.

It is to be noted that the lower edge of the screen 48 is disposed substantially above the bottom of the bowl 40, so that the extracted liquids do not flow back into the receptacle 36 when the apparatus is stopped. When the extracting operation is completed, the chuck 56 may be simply disconnected from the shaft portion 22 and the shaft 24, together with the arm 28, withdrawn upwardly from the housing 12, after which the bowl 40, as a whole, may be removed from the adapter 38 or, alternatively, the drain plug 46 may be removed from the bowl so as to drain the extracted liquid therefrom, while the prepared amalgam filling remains in the receptacle 36.

The receptacle itself may be removed from the annulus 34 for purposes of cleaning, and needless to say the annular side wall of the housing I2 prevents dispersion of any particles such as may fly outwardly from the receptacle 36 or the arm 28 when the device is inmotion.

By adjusting the counterweight 32 on the screw-threaded portion 30 of the arm 28, the arm may be properly counter-balanced in accordance with the amount of material in the receptacle 36, thus assuring even, vibrationless rotation.

It is believed that the advantages and use of the invention will be clearly understood from the foregoing disclosure, and accordingly further description thereof at this point is deemed unnecessary.

Having described the invention, claimed as new is:

A centrifugal extractor, comprising an enclosure including a bottom and a perimetric side wall, a bearing detachably secured in said bottom, a vertical shaft removably and rotatably mounted in said bearing, means for rotating said shaft, a horizontal arm secured intermediate the ends thereof to said shaft, a material receptacle provided at one end of said arm and having an open top and an outer side wall provided with an outwardlyv convergent passage, a longitudiwhat is .nally extending collectingbowl having a dram plug carried by said receptacle and communicating therewith through said passage, a separator screen having a peripheral flange provided at the convergent end of the passage, said flange engaging the outer surface of said bowl and extending inwardly to the interior of said bowl, and an adjustable counter-balance coaxial with and threadedly secured on the remaining end portion of said arm.

HOWARD L. CALL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 504,438 Messler Sept. 5, 1893 1,658,650 Pleister Feb. 7, 1928 1,767,036 Andreson et a1. June 24, 1930 1,832,776 Hudson Nov. 17, 1931 2,060,474 Shriber Nov. 10, 1936 2,202,403 Sandberg May 28, 1940 2,387,782 Tager Oct. 30, 1945 2,418,852 Rothstein Apr. 15, 1947 

